Hey, I'm trying to serialize an object, that has ...

# serialization

[dimitar_]

Hey,

I'm trying to serialize an object, that has an array of LongRange objects - but with no luck.

I have a custom serializer for the LongRange objects

object LongRangeSerializer: KSerializer<LongRange> {
    override val descriptor = buildClassSerialDescriptor("LongRange") {
        element<Long>("first")
        element<Long>("last")
    }

    override fun deserialize(decoder: Decoder): LongRange {
        var first = 0L
        var last = 0L

        decoder.decodeStructure(descriptor) {
            first = decodeLongElement(descriptor, 0)
            last = decodeLongElement(descriptor, 1)
        }

        return first..last
    }

    override fun serialize(encoder: Encoder, value: LongRange) {
        encoder.encodeStructure(descriptor) {
            encodeLongElement(descriptor, 0, value.first)
            encodeLongElement(descriptor, 1, value.last)
        }
    }
}

And I tried:

@Serializable class Container(@Serializable(with = LongRangeSerializer::class) val ranges: Array<LongRange>)

with no luck.

Can't seem to find any pointers anywhere. Tried using a List also, tried also with @Contextual - same issue.

The error is: Kotlin: Serializer has not been found for type 'LongRange'. To use context serializer as fallback, explicitly annotate type or property with @Contextual

[diesieben07]

The property is of type Array<LongRange> so you need to give it a serializer for arrays, not LongRange. In this case ArraySerializer. However that is a top level function, so not sure how to use it with Serializable(with = )

[dimitar_]

Tried something with a custom serializer for Array<LongRange>... but it's the same.

The weird thing is that even if I annotate the field with @Contextual the compiler gives the same error.

[ephemient]

I would have expected

val ranges: Array<@Serializable(with = LongRangeSerializer::class) LongRange>

to work

[ephemient]

but @file:UseSerializers is fine

[dimitar_]

@ephemient thanks! I didn't know you can declare it like that 🙂 I actually prefer your way.